Electrochemical current-generating cells using a light metal anode or negative electrode (in the charged state of the cell) and an aprotic organic electrolyte have generally made use of cathodes (positive electrodes in the charged state of the cell) which consist of mixtures of an active material (e.g. an halogenide, oxide, rhodanide or sulfide of a transition metal, other low-solubility simple or complex salts of the transition metals, sulfur, graphite-fluoride or such organic depolarizers as nitro, nitroso, N-halogeno or quinoidal compounds) with an electrically conductive inert material such as graphite or metal powder.
A satisfactory mechanical stability of such electrodes is obtained by mixing them with synthetic-resin binders and/or by consolidating them under elevated pressure and/or by subjecting them to a temperature treatment designed to prevent distortion in use. The additives to the active material, namely, the syntheticresin binder and conductive inert materials markedly reduce the energy density of the cathode and the latter have significantly poor storage capability.
In the following discussion, reference will be made to primary cells or elements and these are to be understood as designating single-use cells in which chemical energy is converted to electrical energy and the cell is not rechargeable or is only limitedly rechargeable. A secondary cell is one which is rechargeable in the sense that application of electrical energy to the cell reverses the electrochemical process so that a subsequent discharge may again by carried out to produce electrical energy.
The "light metals" within the ambit of the present disclosure are those to be found in the second and third period, groups IA, IIA and IIIA of the Periodic Chart of the Elements (pages 448 and 449 of the HANDBOOK OF CHEMISTRY AND PHYSICS, 41st Edition, 1959-1960).